WesWorld

Type 48, Atlantean Sloop laid down 1948

Intended to replace the Avocet class frigates and relegate the E and P class escort destroyers to coastal defence.

16 ships ordered, more planned

Displacement:
1,200 t light; 1,258 t standard; 1,435 t normal; 1,577 t full load

Dimensions: Length overall / water x beam x draught
327.28 ft / 315.00 ft x 32.00 ft x 11.43 ft (normal load)
99.75 m / 96.01 m x 9.75 m x 3.48 m

Armament:
6 - 3.95" / 100 mm guns (3x2 guns), 30.81lbs / 13.98kg shells, 1948 Model
Dual purpose guns in deck mounts
on centreline ends, majority forward, 1 raised mount - superfiring
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.89kg shells, 1948 Model
Dual purpose guns in deck mounts
on side, all amidships, all raised mounts - superfiring
2 - 1.57" / 40.0 mm guns (1x2 guns), 1.95lbs / 0.89kg shells, 1948 Model
Dual purpose guns in deck mount
on centreline forward, all raised guns - superfiring
12 - 0.79" / 20.0 mm guns (3x4 guns), 0.24lbs / 0.11kg shells, 1948 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
8 - 0.50" / 12.7 mm guns (4x2 guns), 0.06lbs / 0.03kg shells, 1948 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 200 lbs / 91 kg
Shells per gun, main battery: 250
4 - 21.0" / 533.4 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.58" / 40 mm 1.00" / 25 mm -

- Conning tower: 1.00" / 25 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 13,782 shp / 10,281 Kw = 27.00 kts
Range 5,500nm at 15.00 kts
Bunker at max displacement = 318 tons

Complement:
116 - 151

Cost:
£0.821 million / $3.285 million

Distribution of weights at normal displacement:
Armament: 25 tons, 1.7 %
Armour: 21 tons, 1.5 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 18 tons, 1.3 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 3 tons, 0.2 %
Machinery: 337 tons, 23.5 %
Hull, fittings & equipment: 671 tons, 46.8 %
Fuel, ammunition & stores: 235 tons, 16.4 %
Miscellaneous weights: 146 tons, 10.2 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,888 lbs / 856 Kg = 61.3 x 4.0 " / 100 mm shells or 0.7 torpedoes
Stability (Unstable if below 1.00): 1.06
Metacentric height 1.0 ft / 0.3 m
Roll period: 13.4 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.26
Seaboat quality (Average = 1.00): 1.24

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.436
Length to Beam Ratio: 9.84 : 1
'Natural speed' for length: 20.45 kts
Power going to wave formation at top speed: 60 %
Trim (Max stability = 0, Max steadiness = 100): 57
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 5.00 ft / 1.52 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 20.00 ft / 6.10 m
- Forecastle (20 %): 12.60 ft / 3.84 m
- Mid (50 %): 12.60 ft / 3.84 m
- Quarterdeck (15 %): 12.60 ft / 3.84 m
- Stern: 12.60 ft / 3.84 m
- Average freeboard: 13.19 ft / 4.02 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 101.9 %
- Above water (accommodation/working, high = better): 99.3 %
Waterplane Area: 6,603 Square feet or 613 Square metres
Displacement factor (Displacement / loading): 138 %
Structure weight / hull surface area: 55 lbs/sq ft or 268 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.01
- Longitudinal: 3.06
- Overall: 1.12
Hull space for machinery, storage, compartmentation is adequate
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily

80 tons for electronics
8 tons for 4 type 11 torpedo reloads
12 tons for HVAC
24 tons for two type 1 mortar launchers
2 tons for 1x24 round and 2x12 round type 1 spigot motars
20 tons for improved fire control

Looks a decent design overall, I guess you could trim the excess strength a little or use it to increase the freeboard, 12ft seems a little low for an oceanic sloop.

Also trying to get a sense of the layout. Having A & B guns plus a 40mm in C position means a very high bridge quite far back, that is no bad thing (the further aft the less wave motion affects the crew). But I assume the Type 1 mortars are also mounted on the bows or beside the deckhouse there?
It has a lot of AA dakka, no bad thing but it might be a tad overkill for the size of hull (for reference my sloops are 330 x 40 ft and 360 x 41 ft, but are a couple of hundred tons heavier).

Actually the 40mm is supposed to be aft, I didn't notice that in the report so thanks for the catch! The mortars are mounted fore and aft with the after one being mounted above the aft turret and forward of the 40mm mount. The 12 round spigots are on either side of the bridge at deck level just behind B turret position. The 24 round spigot is aft of A turret tucked under the B turret blast shield for A turret, similar to American Buckley class DDE's. Visually they would look similar to the D-22 escort destroyers but with two small funnels and a flush deck. I'm actually thinking about bringing the 4.5" back into service as an auto mount aboard these vessels which would allow me to remove one main mount and free up some deck space.

Here's a tweak on the design that places the 40mm mount aft where it should be as well as adds speed and freeboard. An alternative is to revert to a stepped hull design which might allow for more creative arrangement of weapons.

Type 48, Atlantean Sloop laid down 1948

Displacement:
1,200 t light; 1,258 t standard; 1,435 t normal; 1,577 t full load

Dimensions: Length overall / water x beam x draught
328.01 ft / 315.00 ft x 32.00 ft x 11.43 ft (normal load)
99.98 m / 96.01 m x 9.75 m x 3.48 m

Armament:
6 - 3.95" / 100 mm guns (3x2 guns), 30.81lbs / 13.98kg shells, 1948 Model
Dual purpose guns in deck mounts
on centreline ends, majority forward, 1 raised mount - superfiring
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.88kg shells, 1948 Model
Dual purpose guns in deck mounts
on side, evenly spread, all raised mounts
2 - 1.57" / 40.0 mm guns (1x2 guns), 1.95lbs / 0.88kg shells, 1948 Model
Dual purpose guns in deck mount
on centreline aft, all raised guns - superfiring
12 - 0.79" / 20.0 mm guns (3x4 guns), 0.24lbs / 0.11kg shells, 1948 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
8 - 0.50" / 12.7 mm guns (4x2 guns), 0.06lbs / 0.03kg shells, 1948 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 200 lbs / 91 kg
Shells per gun, main battery: 250
4 - 21.0" / 533.4 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.58" / 40 mm 1.00" / 25 mm -

- Conning tower: 1.00" / 25 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 17,129 shp / 12,778 Kw = 28.50 kts
Range 5,500nm at 15.00 kts
Bunker at max displacement = 318 tons

Complement:
116 - 151

Cost:
£0.907 million / $3.626 million

Distribution of weights at normal displacement:
Armament: 25 tons, 1.7 %
Armour: 21 tons, 1.5 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 18 tons, 1.3 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 3 tons, 0.2 %
Machinery: 419 tons, 29.2 %
Hull, fittings & equipment: 580 tons, 40.4 %
Fuel, ammunition & stores: 235 tons, 16.4 %
Miscellaneous weights: 156 tons, 10.9 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,297 lbs / 588 Kg = 42.1 x 4.0 " / 100 mm shells or 0.5 torpedoes
Stability (Unstable if below 1.00): 1.11
Metacentric height 1.1 ft / 0.3 m
Roll period: 12.8 seconds
Steadiness - As gun platform (Average = 50 %): 71 %
- Recoil effect (Restricted arc if above 1.00): 0.29
Seaboat quality (Average = 1.00): 1.45

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.436
Length to Beam Ratio: 9.84 : 1
'Natural speed' for length: 20.45 kts
Power going to wave formation at top speed: 63 %
Trim (Max stability = 0, Max steadiness = 100): 49
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 5.00 ft / 1.52 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 22.00 ft / 6.71 m
- Forecastle (20 %): 14.60 ft / 4.45 m
- Mid (50 %): 14.60 ft / 4.45 m
- Quarterdeck (15 %): 14.60 ft / 4.45 m
- Stern: 14.60 ft / 4.45 m
- Average freeboard: 15.19 ft / 4.63 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 120.8 %
- Above water (accommodation/working, high = better): 115.0 %
Waterplane Area: 6,603 Square feet or 613 Square metres
Displacement factor (Displacement / loading): 118 %
Structure weight / hull surface area: 42 lbs/sq ft or 206 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.73
- Longitudinal: 3.75
- Overall: 0.86
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily

80 tons for electronics
8 tons for 4 type 11 torpedo reloads
12 tons for HVAC
24 tons for two type 1 mortar launchers
2 tons for 1x24 round and 2x12 round type 1 spigot motars
20 tons for improved fire control

Looks good and your description makes much more sense now.

Its still got quite abit of hull strength so I might play with it abit more but I'd like to keep it to a maximum of 1,200 tons.

Not many tweaks on this design but it should be an extremely sturdy ship in the Atlantic. I simply made the aft twin 40mm a quad instead.

Type 48, Atlantean Sloop laid down 1948

Displacement:
1,200 t light; 1,259 t standard; 1,436 t normal; 1,578 t full load

Dimensions: Length overall / water x beam x draught
328.26 ft / 315.25 ft x 32.00 ft x 11.43 ft (normal load)
100.05 m / 96.09 m x 9.75 m x 3.48 m

Armament:
6 - 3.95" / 100 mm guns (3x2 guns), 30.81lbs / 13.98kg shells, 1948 Model
Dual purpose guns in deck mounts
on centreline ends, majority forward, 1 raised mount - superfiring
4 - 1.57" / 40.0 mm guns (2x2 guns), 1.95lbs / 0.88kg shells, 1948 Model
Dual purpose guns in deck mounts
on side, all amidships, all raised mounts - superfiring
4 - 1.57" / 40.0 mm guns (1x4 guns), 1.95lbs / 0.88kg shells, 1948 Model
Dual purpose guns in deck mount
on centreline aft, all raised guns - superfiring
12 - 0.79" / 20.0 mm guns (3x4 guns), 0.24lbs / 0.11kg shells, 1948 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
8 - 0.50" / 12.7 mm guns (4x2 guns), 0.06lbs / 0.03kg shells, 1948 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 204 lbs / 92 kg
Shells per gun, main battery: 250
4 - 21.0" / 533.4 mm above water torpedoes

Armour:
- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 1.58" / 40 mm 1.00" / 25 mm -

- Conning tower: 1.00" / 25 mm

Machinery:
Diesel Internal combustion motors,
Geared drive, 2 shafts, 17,131 shp / 12,780 Kw = 28.50 kts
Range 5,500nm at 15.00 kts
Bunker at max displacement = 319 tons

Complement:
116 - 151

Cost:
£0.910 million / $3.639 million

Distribution of weights at normal displacement:
Armament: 25 tons, 1.8 %
Armour: 21 tons, 1.5 %
- Belts: 0 tons, 0.0 %
- Torpedo bulkhead: 0 tons, 0.0 %
- Armament: 18 tons, 1.3 %
- Armour Deck: 0 tons, 0.0 %
- Conning Tower: 3 tons, 0.2 %
Machinery: 419 tons, 29.1 %
Hull, fittings & equipment: 579 tons, 40.3 %
Fuel, ammunition & stores: 236 tons, 16.4 %
Miscellaneous weights: 156 tons, 10.9 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
1,294 lbs / 587 Kg = 42.0 x 4.0 " / 100 mm shells or 0.5 torpedoes
Stability (Unstable if below 1.00): 1.12
Metacentric height 1.1 ft / 0.3 m
Roll period: 12.7 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.29
Seaboat quality (Average = 1.00): 1.45

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.436
Length to Beam Ratio: 9.85 : 1
'Natural speed' for length: 20.45 kts
Power going to wave formation at top speed: 63 %
Trim (Max stability = 0, Max steadiness = 100): 48
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 5.00 ft / 1.52 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 22.00 ft / 6.71 m
- Forecastle (20 %): 14.60 ft / 4.45 m
- Mid (50 %): 14.60 ft / 4.45 m
- Quarterdeck (15 %): 14.60 ft / 4.45 m
- Stern: 14.60 ft / 4.45 m
- Average freeboard: 15.19 ft / 4.63 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 121.0 %
- Above water (accommodation/working, high = better): 115.1 %
Waterplane Area: 6,608 Square feet or 614 Square metres
Displacement factor (Displacement / loading): 118 %
Structure weight / hull surface area: 42 lbs/sq ft or 206 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 0.73
- Longitudinal: 3.74
- Overall: 0.86
Hull space for machinery, storage, compartmentation is cramped
Room for accommodation and workspaces is adequate
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily

80 tons for electronics
8 tons for 4 type 11 torpedo reloads
12 tons for HVAC
24 tons for two type 1 mortar launchers
2 tons for 1x24 round and 2x12 round type 1 spigot motars
20 tons for improved fire control

I'm considering building purpose built aircraft tenders rather than convert older vessels, Nautica may also be converted to this role as she is abit redundant in her role as training carrier.

Perdix/Talos, Atlantean Aircraft carrier tender laid down 1949

Displacement:
19,997 t light; 20,641 t standard; 23,195 t normal; 25,238 t full load

Dimensions: Length overall / water x beam x draught
698.10 ft / 675.00 ft x 96.00 ft x 23.20 ft (normal load)
212.78 m / 205.74 m x 29.26 m x 7.07 m

Armament:
12 - 3.95" / 100 mm guns (6x2 guns), 30.81lbs / 13.98kg shells, 1949 Model
Automatic rapid fire guns in deck mounts with hoists
on side, evenly spread, all raised mounts
16 - 0.79" / 20.0 mm guns (4x4 guns), 0.24lbs / 0.11kg shells, 1949 Model
Anti-aircraft guns in deck mounts
on side, evenly spread, all raised mounts
8 - 0.50" / 12.7 mm guns (4x2 guns), 0.06lbs / 0.03kg shells, 1949 Model
Machine guns in deck mounts
on side, evenly spread, all raised mounts
Weight of broadside 374 lbs / 170 kg
Shells per gun, main battery: 850

Armour:
- Belts: Width (max) Length (avg) Height (avg)
Main: 3.95" / 100 mm 345.00 ft / 105.16 m 10.00 ft / 3.05 m
Ends: Unarmoured
Main Belt covers 79 % of normal length
Main belt does not fully cover magazines and engineering spaces

- Torpedo Bulkhead:
1.96" / 50 mm 345.00 ft / 105.16 m 23.00 ft / 7.01 m

- Gun armour: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 2.00" / 51 mm 1.00" / 25 mm 1.58" / 40 mm
2nd: 1.00" / 25 mm - -

- Armour deck: 3.95" / 100 mm, Conning tower: 1.00" / 25 mm

Machinery:
Oil fired boilers, steam turbines,
Geared drive, 4 shafts, 97,460 shp / 72,705 Kw = 30.15 kts
Range 15,000nm at 15.00 kts
Bunker at max displacement = 4,597 tons

Complement:
939 - 1,221

Cost:
£8.223 million / $32.893 million

Distribution of weights at normal displacement:
Armament: 56 tons, 0.2 %
Armour: 4,666 tons, 20.1 %
- Belts: 620 tons, 2.7 %
- Torpedo bulkhead: 575 tons, 2.5 %
- Armament: 45 tons, 0.2 %
- Armour Deck: 3,408 tons, 14.7 %
- Conning Tower: 18 tons, 0.1 %
Machinery: 2,356 tons, 10.2 %
Hull, fittings & equipment: 7,373 tons, 31.8 %
Fuel, ammunition & stores: 3,197 tons, 13.8 %
Miscellaneous weights: 5,546 tons, 23.9 %

Overall survivability and seakeeping ability:
Survivability (Non-critical penetrating hits needed to sink ship):
45,069 lbs / 20,443 Kg = 1,462.6 x 4.0 " / 100 mm shells or 7.8 torpedoes
Stability (Unstable if below 1.00): 1.15
Metacentric height 6.1 ft / 1.9 m
Roll period: 16.3 seconds
Steadiness - As gun platform (Average = 50 %): 70 %
- Recoil effect (Restricted arc if above 1.00): 0.03
Seaboat quality (Average = 1.00): 1.20

Hull form characteristics:
Hull has a flush deck
and transom stern
Block coefficient: 0.540
Length to Beam Ratio: 7.03 : 1
'Natural speed' for length: 30.39 kts
Power going to wave formation at top speed: 55 %
Trim (Max stability = 0, Max steadiness = 100): 58
Bow angle (Positive = bow angles forward): 20.00 degrees
Stern overhang: 10.00 ft / 3.05 m
Freeboard (% = measuring location as a percentage of overall length):
- Stem: 36.00 ft / 10.97 m
- Forecastle (25 %): 22.00 ft / 6.71 m
- Mid (50 %): 22.00 ft / 6.71 m
- Quarterdeck (15 %): 22.00 ft / 6.71 m
- Stern: 22.00 ft / 6.71 m
- Average freeboard: 23.40 ft / 7.13 m

Ship space, strength and comments:
Space - Hull below water (magazines/engines, low = better): 78.9 %
- Above water (accommodation/working, high = better): 208.1 %
Waterplane Area: 46,632 Square feet or 4,332 Square metres
Displacement factor (Displacement / loading): 151 %
Structure weight / hull surface area: 118 lbs/sq ft or 577 Kg/sq metre
Hull strength (Relative):
- Cross-sectional: 1.01
- Longitudinal: 1.27
- Overall: 1.03
Hull space for machinery, storage, compartmentation is excellent
Room for accommodation and workspaces is excellent
Ship has slow, easy roll, a good, steady gun platform
Good seaboat, rides out heavy weather easily

This ship is designed to operate as support CV. Machinery is same type as in the Phoenix class heavy cruiser
The main armament of 3.95" is a new mark using same half deck turrets as 5.1 mk 4/55 with modified auto loading equipment
Hangar deck has 3" of armor, flight deck has 2" (1.02" simmed using misc weight)

1,300 tons for 36 operational aircraft
1,200 tons for aircraft spare parts
906 tons used to sim 1.05" of deck armor
900 tons for 36 spare aircraft (25 tons each)
200 tons for Machine shop
200 tons for engine repair shop
200 tons for fabrication shop
150 tons for electronics
100 tons for 2 lighters and their associated equipment and fuel
100 tons for 2x50ton cranes
100 tons for T shaped lift
100 tons for fire screens and damage control equipment
50 tons for catapult
40 tons for 4x300kw diesel generators

Having built such ships myself, I would say go for it. Two would be more than generous I think for the size of the Atlantean fleet and at least allows you to rotate their deployment.
They would make a good back up carrier option too. Handling heavier jets might be an issue but generally unless you have a crystal ball then its hard to avoid that pitfall in the longer term. In any case even if you can't fly aircraft on and off by the end of the 1950s you still have a good tender and lots of parking space.

My thinking is that other than Atlantis proper most bases have limits to their aircraft maintenance facilities, these ships would give a boost when and where it is needed and as you say could be rotated.